Improvement in crank and piston connections for steam-engines



s. P. RUG GLES Crank and Piston Connections for Steam-Engines.

N0 157,765, Patented Dec.15,1874.

15011 0121211 fl bawma UNITED STATES PATENT QFFICE.

STEPHEN P. RUGGLES, OF BOSTON, MASSAUHUSETTS.

IMPROVEMENT IN CRANK AND PISTON CONNECTIONS FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 157,765, dated December15, 1874; application filed November 27, 1874.

To all whom it may concern:

Be it known that I, STEPHEN P. RUGGLES, of Boston, in the county ofSuffolk and State of Massachusetts, have invented certain new and usefulImprovements in Crank and Piston or Pit-man Connections for Steam-Engines; and I do hereby declare the following to be a full, clear, andexact description of the same, reference being had to the accompanyingdrawings making a part of this specification, in which- Figure 1represents a plan, and Fig.2 a top View, of so much of a horizontalsteam-engine as will illustrate my invention.

The object of my invention is to'relieve the balance-wheel shaft of asteam-engine of the strain and pressure there is upon it when the crankis passing the dead-centers and the steam first let in at either end ofthe cylinder, and this I accomplish by using comparati vely a longcrankmuch longer. than half of the stroke of the piston-and getting alonger leverage 011 the crank out of the dead-center line at the timethat the steam is first let into the cylinder; and my invention consistsin a longitudinal or radial slot in the crank, in which a slide or blockcarrying the wrist-pin can traverse, said slide or block being guided inits movements by a friction-roll running against a cam or guide toelongate the crank during the working portions of its rotation, andshorten it to pass the dead centers, as will be explained.

To enable others skilled in the art to make and use my invention, I willproceed to describe the samewith reference to the drawings, firstpremising that an arrangement of oblique slot in a crank, with a pinmoving thereimwithout a guide of any kind, has been essayed inconnection with a steam-engine, but for what useful purpose I am unableto say. To such an arrangement I make no claim whatever.

In the drawings, A represents a steam-cylind er having the usual inletand exhaust ports. In this cylinder is the piston-head B, to which thepiston-rod G is attached, the latter passing out through a stuffing-box,a, in

the usual well-known way. To the piston-rod Y 0 there is pivoted, as atb, the connecting-rod or pitman D. On one end of a shaft, 0, supportedin suitable hearings in the bed-piece E, is placed the balance-wheel F,and upon the opposite end of said shaft is placed the crank G, andbetween the crank and bedpiece is placed a cam or guide, H. In the crankarm G there is a longitudinal slot, 6, in which a block, 2', is placedor fitted, so that it can freely traverse through said slot, and in oron this block there is a wristpin, a, to which the end of theconnecting-rod or pitman D is attached. On or in the block '5 there isalso a friction -roll, m, which is held and runs against the cam orguide H by the action of the steam, and moves said block and pin in theslot 0 of the crank-arm, lengthening or shortening the crank, as thecase may be. v

The wrist-pin n and the head or friction roll m may be in one piece, andturn in the slide or block t, while, of course, it always moves with theslide longitudinally of the crank.

It will be perceived, on reference to Fig. 1, that when the piston isready to start, on admitting steam behind it, the crank has beenelongated, and the connecting-rod and wristpin have passed so far beyondthe line of dead-centers that the power of the steam is economicallyapplied to turning the crank and balance-wheel, and does not comeagainst the bearings of the balance-wheel shaft, as would be the casewith the common crank, or short crank, such as are commonly used.

Having thus fully described my invention, what I claim is-- Incombination with the piston of a steamengine and its rod-connection withthe crank, the slot in said crank and slide or block therein, havingconnected to or with it the wristpin and head or roll, and thestationary guide or cam, as and for the purpose described andrepresented.

STEPHEN P. RUGGLES. Witnesses:

MELVILLE M. WESTON, CHARLES ALBERT PRINCE.

